1903.] FISHES FROM RIO JANEIRO. 67 



as in S'. saliens, and the maxillary extends to below the posterior 

 margin of the eye ; the lattei' has a more slender body than any 

 other species of this section, and the maxillary not reaching the 

 posterior margin of the eye ; like *S'. saliens, it occurs on both the 

 Atlantic and Pacific coasts. A fifth species, S. mundus Jordan & 

 Starks, from the Pacific Coast of Central America, is said to 

 differ from S. alius in having a larger mouth ; an example received 

 from Dr. Jordan under this name has only four spines in the 

 anterior dorsal, and is identical with S. saliens : it may be that 

 the number of spines is vaiiable in this species. 



SCOMBRID^E. 



American ichthyologists distinguish between Scomhromorus 

 regalis Bloch and ^S'. maculatths Mitchill ; but the supposed 

 differences are so few, so trivial, aiid, judging by the few specimens 

 I have been able to examine, so inconstant, that there can be but 

 little doubt that the two are not distinct, and that the latter 

 should be added to the synonymy of the former. American 

 authors also agree in considering Gyhium immaculatuin Cuv. & 

 Val. to be a synonym of Scombroinorus cavalla Cuv. & Val. I am 

 inclined to think, however, that two small examples in the 

 British Museum Collection should be referred to S. immacidatus, 

 and that they are specifically distinct from S. cavalla, two large 

 examples of which are included in Dr. Goeldi's collection. The 

 number of fin-rays is the same and the course of the lateral line 

 similar in both species, and the differences will be apparent from 

 the following short comparison : — 



SCOMBROMORUS CAVALLA CuV. & Yal. 



Depth of body Sg-Sj times in total length, length of head 

 4| times ; depth of head (at level of upper angle of gill-opening) 

 1-| times in its length, diameter of eye 6-6 1 times. Gill-rakers 

 nearly equal to \ eye-diameter, 8 on lower part of anterior arch. 

 Jaws with about 1 5 teeth on each side. Body dark above, silvery 

 below, with traces of dark oval spots on the sides. 



Two specimens, 560 and 620 mm. in total length, from Rio 

 Janeiro. 



ScOMBROMORUS IMMACULATUS CuV, ife Val. 



Depth of body 34-4 times in total length, length of head 5 times ; 

 depth of head 1^ times in its length, diameter of eye 4|-4i times. 

 Gill-rakers knob-like rudiments, 8-9 on lower part of anterior 

 arch. Jaws with 8-10 teeth on each side. Body dark above, 

 silvery on sides and below, without spots. 



Two specimens, 150 and 185 mm., from San Domingo. 



Ophidiid.e. 



The genus GenijjJterus Philippi is distinguished from Lep- 

 ophidvmn Gill by the stronger dentition, the outer series of teeth 



5* 



